In his reflection before praying the Regina Caeli today, Pope Benedict XVI spoke of Pentecost as the celebration of the birth of the Church, as Mary and the Apostles were gathered at the time of the descent of the Holy Spirit. He mentioned its missionary nature from the beginning, and thus spoke in every tongue. He also explained the phrase "one Holy, Catholic and Apostolic Church" from the 4th century Nicene Creed, explained what was meant in calling the Church "Roman."
The greater part of it, in Teresa Benedetta's translation, includes those explanations of the words we use to describe the Church, as follows:
"In this extraordinary event we find the essential and qualifying notes of the Church: the Church is one, like the community of Pentecost, united in prayer and concord: it was 'of one heart and one mind" (Acts 4,32). The Church is holy, not for its merits, but because, animated by the Holy Spirit, it looks to Christ to conform to Him and to his love. The Church is catholic, because the Gospel is destined to all the peoples, and therefore, from the beginning, the Holy Spirit made it speak in all tongues. The Church is apostolic, because, built on the foundation of the Apostles, it guards their teaching faithfully through the uninterrupted chain of apostolic succession.
"The Church is also by its nature missionary, and from the day of Pentecost, the Holy Spirit has not ceased to push it along the roads of the world, to the extreme ends of earth and to the end of time.
"This reality, which we can verify in every era, is as anticipated in the Book of Acts, which describes the transmission of the Gospel from the Jews to the pagans, from Jerusalem to Rome.
"Rome stood for the pagan world, therefore all the peoples who were not among the ancient People of God. In fact, the Acts conclude with the arrival of the Gospel in Rome.
"We can therefore say that Rome is the concrete name of Catholicity and mission, it expresses loyalty to the origins, to the Church of all time, a Church that speaks all the languages and goes forth to encounter all cultures."